The present invention relates to an embroidery sewing machine and more particularly relates to a stitching speed control of the sewing machine during embroidery stitching operations
It is generally known that the embroidery sewing machine has an embroidering frame provided thereto, the embroidering frame having a work held thereon to be embroidered and being moved in the X-Y direction relative to a vertically reciprocating needle in synchronism with the reciprocating movement of the needle.
In this connection, it is required that the embroidering frame is moved from one to another position while the needle is moved up so as to have stitches formed on the work held by the embroidering frame. The vertical reciprocating speed of the needle (stitching speed) is, therefore, normally decided to meet a maximum distance that is traversed by the embroidering frame while the needle is in the upper position so that the embroidering frame may be safely moved a long distance between two positions.
Such a set speed of the vertically reciprocating needle is constant regardless of the distances short and long that are traversed by the embroidering frame. Therefore, it takes a long time to stitch up one complete pattern. Various devices have been proposed to increase the vertical moving speed of the needle in case the distance that is traversed by the embroidering frame is short. One of the devices is disclosed, for example, in U.S. Pat. No. 5,764,031. Such prior art is, however, designed to give consideration only to the distances to be traversed by the embroidering frame and fails to give consideration to other problems to be solved.
The invention has been provided to eliminate the defects and disadvantages of the prior art. It is, therefore, a primary object of the invention to control a stitching speed in consideration of the size and weight of an embroidering frame and a work held by the embroidering frame as well as in consideration of the distance to be traversed by the embroidering frame.
It is another object of the invention to control the stitching speed in dependence upon a position of the embroidering frame during stitching operation.
It is another object of the invention to reduce the moving speed of the embroidering frame in case the same is comparatively heavy so as to reduce a load to an X-Y moving mechanism.
It is another object of the invention to reduce the moving speed of the embroidering frame in case the same carries a thick and/or heavy work to be stitched.
It is still another object of the invention to reduce the moving speed of the embroidering frame as the embroidering frame is partly moved away from the body of sewing machine so as to maintain a stabilized stitching operation without vibrations.
In short, the embroidery sewing machine comprises a stitch forming device including a needle vertically reciprocated to form stitches on a work to be stitched, a moving member including a member for holding the work and being moved relative to the needle in synchronism with the needle, a memory for storing stitch data therein for deciding the positions to which the moving member is moved in accordance with a shape of a pattern to be embroidered, means for giving information regarding the moving member, means for detecting the position of the work, means for controlling the speed of stitching operation of the stitch forming device by use of the information regarding the moving member and the position of the work as parameters, the information regarding the moving member including data of at least one of the thickness, weight and material of the work and data of at least one of the size and weight of the work holding member, the speed control means controlling the stitching speed of the stitch forming device by limiting a maximum speed of the stitch forming device, or by successively calculating out the stitching speed of the stitch forming device, and further by reducing the stitching speed of the stitch forming device as the weight of embroidering frame increases, as the thickness of the work increases and as the moving member is partly moved away from the body of the sewing machine. The embroidery sewing machine further may comprise means for entering the information regarding the moving member and means for detecting the information regarding the moving member.